overdiagnosis

Cancer screening tests are not perfect. Test results may suggest cancer when there is none (false-positive screen). They can also miss cancer even if it is present (false-negative screen). False-positive results can lead to emotional stress and more testing without improving health. Screening tests may also lead to overdiagnosis. Overdiagnosis is when screening tests find slow-growing forms of cancer that would never have caused symptoms or affected health if left undetected.